While annually over 1/2 million American children visit the emergency room with a head injury, many aspects of pediatric traumatic brain injury (TBI) are still not well understood. Researchers have been making great strides toward a better understanding of TBI to help fulfill the mission of the NICHD to ensure ...that all children have the chance to achieve their full potential for healthy and productive lives, free from disease or disability, and to ensure the health, productivity, independence, and well-being of all people through optimal rehabilitation. For pediatric TBI, this research is particularly challenging and costly to conduct. Thus, most studies are small with limited information about differences across populations. Only analyzing several studies together would permit the discovery of symptom differences across broad spectra of injuries and demographics. There has already been some development of statistical methods for jointly analyzing small collections of longitudinal data. This work has established a general framework for approaching this problem, but has not filled in the details of how to deal with real-world data complications. The broad goal of this proposal is to establish the feasibility and benefit of jointly analyzing similar studies of pediatric TBI through a case study of the variation in TBI recovery across age at injury. The specific aims of the project are to: 1. Use currently available meta-analytic methods to study the effect of age at injury on short- and long- term symptoms of TBI using two completed observational study datasets, while simultaneously precisely identifying current methodological limitations. 2. Develop new statistical methods based on established meta-analytic and missing data approaches to jointly analyze pediatric TBI datasets from observational studies. 3. Identify next steps for creating the Ohio Pediatric TBI Data Bank. The OPT Data Bank would be a data warehouse for studies of pediatric TBI originating at one of the three major Ohio children's hospitals. It would facilitate improved studies of pediatric TBI via the joint analysis of a larger data set, and would serve as a model for data sharing in a wide range of similar fields. The achievement of these aims will pave the way for improved understanding of the effects of TBI in the pediatric population. In turn, this will lead to improved treatment of these children and adolescents. Second, the newly developed statistical methods will be applicable to a broad range of similar medical areas, thus significantly improving the evidence base for making sound patient-centered decisions.